Before you read, be aware that I have searched using google and this forum.

I am looking for a less expensive than OEM alternative rear rotor for my 2010 F650GS Twin. I cannot find any. All search results I get are for front rotors or for rear F650GS single / F650GS models or for F800GS models, etc. EBC does not list one, Galfer does not list one (it would probably be more expensive than stock), etc. Before you make a recommendation or make general search suggestions, please double check it yourself.

That looks like it is for an F800GS. The rear rotors on the F650GS are different as far as I know.

Nope. Rear is the same. The front is different.

I've actually got an f800gs rear hub on my 650 twin and used my existing rear disc. If you want 100% confirmation check the microfiche on Max BMW website or Bike Bandit. The part numbers are the same for both bikes.